1
|
Giorgi V, Amicucci A, Landi L, Castelli I, Romanazzi G, Peroni C, Ranocchi B, Zambonelli A, Neri D. Effect of Bacteria Inoculation on Colonization of Roots by Tuber melanosporum and Growth of Quercus ilex Seedlings. PLANTS (BASEL, SWITZERLAND) 2024; 13:224. [PMID: 38256777 PMCID: PMC10819665 DOI: 10.3390/plants13020224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
Tuber melanosporum is an ascomycete that forms ectomycorrhizal (ECM) symbioses with a wide range of host plants, producing edible fruiting bodies with high economic value. The quality of seedlings in the early symbiotic stage is important for successful truffle cultivation. Numerous bacterial species have been reported to take part in the truffle biological cycle and influence the establishment of roots symbiosis in plant hosts and the development of the carpophore. In this work, three different bacteria formulations were co-inoculated in Quercus ilex L. seedlings two months after T. melanosporum inoculation. At four months of bacterial application, the T. melanosporum ECM root tip rate of colonization and bacterial presence were assessed using both morphological and molecular techniques. A 2.5-fold increase in ECM colonization rate was found in the presence of Pseudomonas sp. compared to the seedlings inoculated only with T. melanosporum. The same treatment caused reduced plant growth either for the aerial and root part. Meanwhile, the ECM colonization combined with Bradyrhizobium sp. and Pseudomonas sp. + Bradyrhizobium sp. reduced the relative density of fibrous roots (nutrient absorption). Our work suggests that the role of bacteria in the early symbiotic stages of ECM colonization involves both the mycorrhizal symbiosis rate and plant root development processes, both essential for improve the quality of truffle-inoculated seedlings produced in commercial nurseries.
Collapse
Affiliation(s)
- Veronica Giorgi
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (V.G.); (L.L.); (I.C.); (G.R.); (D.N.)
| | - Antonella Amicucci
- Department of Biomolecular Sciences, University of Urbino “Carlo Bo”, 61029 Urbino, Italy;
| | - Lucia Landi
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (V.G.); (L.L.); (I.C.); (G.R.); (D.N.)
| | - Ivan Castelli
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (V.G.); (L.L.); (I.C.); (G.R.); (D.N.)
| | - Gianfranco Romanazzi
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (V.G.); (L.L.); (I.C.); (G.R.); (D.N.)
| | - Cristiano Peroni
- Agenzia per l’Innovazione nel Settore Agroalimentare e della Pesca “Marche Agricoltura Pesca”, AMAP, 60027 Osimo, Italy;
| | - Bianca Ranocchi
- Department of Biomolecular Sciences, University of Urbino “Carlo Bo”, 61029 Urbino, Italy;
| | - Alessandra Zambonelli
- Department of Agricultural and Food Sciences, University of Bologna, 40127 Bologna, Italy;
| | - Davide Neri
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy; (V.G.); (L.L.); (I.C.); (G.R.); (D.N.)
| |
Collapse
|
2
|
Wang B, McCormack ML, Ricciuto DM, Yang X, Iversen CM. Embracing fine-root system complexity in terrestrial ecosystem modeling. GLOBAL CHANGE BIOLOGY 2023; 29:2871-2885. [PMID: 36861355 DOI: 10.1111/gcb.16659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 02/15/2023] [Indexed: 05/03/2023]
Abstract
Projecting the dynamics and functioning of the biosphere requires a holistic consideration of whole-ecosystem processes. However, biases toward leaf, canopy, and soil modeling since the 1970s have constantly left fine-root systems being rudimentarily treated. As accelerated empirical advances in the last two decades establish clearly functional differentiation conferred by the hierarchical structure of fine-root orders and associations with mycorrhizal fungi, a need emerges to embrace this complexity to bridge the data-model gap in still extremely uncertain models. Here, we propose a three-pool structure comprising transport and absorptive fine roots with mycorrhizal fungi (TAM) to model vertically resolved fine-root systems across organizational and spatial-temporal scales. Emerging from a conceptual shift away from arbitrary homogenization, TAM builds upon theoretical and empirical foundations as an effective and efficient approximation that balances realism and simplicity. A proof-of-concept demonstration of TAM in a big-leaf model both conservatively and radically shows robust impacts of differentiation within fine-root systems on simulating carbon cycling in temperate forests. Theoretical and quantitative support warrants exploiting its rich potentials across ecosystems and models to confront uncertainties and challenges for a predictive understanding of the biosphere. Echoing a broad trend of embracing ecological complexity in integrative ecosystem modeling, TAM may offer a consistent framework where modelers and empiricists can work together toward this grand goal.
Collapse
Affiliation(s)
- Bin Wang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Daniel M Ricciuto
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Xiaojuan Yang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Colleen M Iversen
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| |
Collapse
|
3
|
Tang Y, Schiestl-Aalto P, Saurer M, Sahlstedt E, Kulmala L, Kolari P, Ryhti K, Salmon Y, Jyske T, Ding Y, Bäck J, Rinne-Garmston KT. Tree organ growth and carbon allocation dynamics impact the magnitude and δ13C signal of stem and soil CO2 fluxes. TREE PHYSIOLOGY 2022; 42:2404-2418. [PMID: 35849053 PMCID: PMC10101690 DOI: 10.1093/treephys/tpac079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/08/2022] [Accepted: 07/02/2022] [Indexed: 05/14/2023]
Abstract
Incomplete knowledge of carbon (C) allocation dynamics in trees hinders accurate modeling and future predictions of tree growth. We studied C allocation dynamics in a mature Pinus sylvestris L. dominated forest with a novel analytical approach, allowing the first comparison of: (i) magnitude and δ13C of shoot, stem and soil CO2 fluxes (Ashoot, Rstem and Rsoil), (ii) concentration and δ13C of compound-specific and/or bulk non-structural carbohydrates (NSCs) in phloem and roots and (iii) growth of stem and fine roots. Results showed a significant effect of phloem NSC concentrations on tracheid growth, and both variables significantly impacted Rstem. Also, concentrations of root NSCs, especially starch, had a significant effect on fine root growth, although no effect of root NSC concentrations or root growth was detected on Rsoil. Time series analysis between δ13C of Ashoot and δ13C of Rstem or δ13C of Rsoil revealed strengthened C allocation to stem or roots under high C demands. Furthermore, we detected a significant correlation between δ13C of Rstem and δ13C of phloem sucrose and glucose, but not for starch or water-soluble carbohydrates. Our results indicate the need to include C allocation dynamics into tree growth models. We recommend using compound-specific concentration and δ13C analysis to reveal C allocation processes that may not be detected by the conventional approach that utilizes bulk organic matter.
Collapse
Affiliation(s)
| | - Pauliina Schiestl-Aalto
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape
Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Elina Sahlstedt
- Bioeconomy and Environment Unit, Natural Resources Institute
Finland, Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Liisa Kulmala
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
- Finnish Meteorological Institute, P.O. Box 503, FI-00101
Helsinki, Finland
| | - Pasi Kolari
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Kira Ryhti
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Tuula Jyske
- Production Systems Unit, Natural Resources Institute Finland,
Tietotie 2, FI-02150 Espoo, Finland
| | - Yiyang Ding
- Department of Forest Sciences, Faculty of Agriculture and
Forestry, University of Helsinki, P.O. Box 27, FI-00014
Helsinki, Finland
| | - Jaana Bäck
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
| | - Katja T Rinne-Garmston
- Bioeconomy and Environment Unit, Natural Resources Institute
Finland, Latokartanonkaari 9, FI-00790 Helsinki, Finland
| |
Collapse
|
4
|
Wang C, Brunner I, Wang J, Guo W, Geng Z, Yang X, Chen Z, Han S, Li MH. The Right-Skewed Distribution of Fine-Root Size in Three Temperate Forests in Northeastern China. FRONTIERS IN PLANT SCIENCE 2022; 12:772463. [PMID: 35069627 PMCID: PMC8777189 DOI: 10.3389/fpls.2021.772463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Trees can build fine-root systems with high variation in root size (e.g., fine-root diameter) and root number (e.g., branching pattern) to optimize belowground resource acquisition in forest ecosystems. Compared with leaves, which are visible above ground, information about the distribution and inequality of fine-root size and about key associations between fine-root size and number is still limited. We collected 27,573 first-order fine-roots growing out of 3,848 second-order fine-roots, covering 51 tree species in three temperate forests (Changbai Mountain, CBS; Xianrendong, XRD; and Maoershan, MES) in Northeastern China. We investigated the distribution and inequality of fine-root length, diameter and area (fine-root size), and their trade-off with fine-root branching intensity and ratio (fine-root number). Our results showed a strong right-skewed distribution in first-order fine-root size across various tree species. Unimodal frequency distributions were observed in all three of the sampled forests for first-order fine-root length and area and in CBS and XRD for first-order fine-root diameter, whereas a marked bimodal frequency distribution of first-order fine-root diameter appeared in MES. Moreover, XRD had the highest and MES had the lowest inequality values (Gini coefficients) in first-order fine-root diameter. First-order fine-root size showed a consistently linear decline with increasing root number. Our findings suggest a common right-skewed distribution with unimodality or bimodality of fine-root size and a generalized trade-off between fine-root size and number across the temperate tree species. Our results will greatly improve our thorough understanding of the belowground resource acquisition strategies of temperate trees and forests.
Collapse
Affiliation(s)
- Cunguo Wang
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
| | - Ivano Brunner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Junni Wang
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
| | - Wei Guo
- College of Agronomy, Shenyang Agricultural University, Shenyang, China
| | - Zhenzhen Geng
- College of Agronomy, Shenyang Agricultural University, Shenyang, China
| | - Xiuyun Yang
- College of Forestry, Shanxi Agricultural University, Taigu, China
| | - Zhijie Chen
- International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, China
| | - Shijie Han
- International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, China
| | - Mai-He Li
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| |
Collapse
|
5
|
Montagnoli A, Baronti S, Alberto D, Chiatante D, Scippa GS, Terzaghi M. Pioneer and fibrous root seasonal dynamics of Vitis vinifera L. are affected by biochar application to a low fertility soil: A rhizobox approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:141455. [PMID: 32889452 DOI: 10.1016/j.scitotenv.2020.141455] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/01/2020] [Accepted: 08/01/2020] [Indexed: 05/02/2023]
Abstract
The present work analyzes the impact of biochar-induced modification of soil physico-chemical properties on intra-annual growth dynamics of pioneer and fibrous grapevine roots. A scanner inserted into a buried rhizobox with a transparent side facing the plant root system was used to acquire images of pioneer and fibrous roots of control and biochar-treated plants throughout the vegetative season. Images were analyzed with ImageJ software to measure root traits. Biochar treatment increased soil pH, nutrient concentration, and water content during the driest and warmest period, while bulk density was reduced. Analysis of both pioneer and fibrous root traits highlighted a single peak of growth during the vegetative season. Pioneer roots were thicker and grew faster than fibrous roots, which were longer and more numerous. Amelioration of physico-chemical properties of biochar-amended soil stimulated an earlier root lengthening, and a higher root number at the onset of the season, which resulted in a greater canopy development compared to control plants. Later, in summer, as a consequence of the higher water content of biochar-treated soil, plants modified their root architecture, lowering the number of fibrous roots probably because of the reduced need to exploit soil for water and nutrient uptake.
Collapse
Affiliation(s)
- Antonio Montagnoli
- University of Insubria, Department of Biotechnology and Life Science, Via Dunant, 3, 21100 Varese, Italy.
| | - Silvia Baronti
- Institute of BioEconomy, National Research Council, via Caproni, 8, 50145 Firenze, Italy
| | - Danieli Alberto
- University of Insubria, Department of Science and High Technology, Via Valleggio, 11, 22100 Como, Italy
| | - Donato Chiatante
- University of Insubria, Department of Biotechnology and Life Science, Via Dunant, 3, 21100 Varese, Italy
| | - Gabriella Stefania Scippa
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Isernia, Italy
| | - Mattia Terzaghi
- University of Insubria, Department of Biotechnology and Life Science, Via Dunant, 3, 21100 Varese, Italy
| |
Collapse
|
6
|
López-Bernal Á, García-Tejera O, Testi L, Villalobos FJ. Genotypic variability in radial resistance to water flow in olive roots and its response to temperature variations. TREE PHYSIOLOGY 2020; 40:445-453. [PMID: 32031664 DOI: 10.1093/treephys/tpaa010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/30/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
As radial root resistance (Rp) represents one of the key components of the soil-plant-atmosphere continuum resistance catena modulating water transport, understanding its control is essential for physiologists, modelers and breeders. Reports of Rp, however, are still scarce and scattered in the scientific literature. In this study, we assessed genetic variability in Rp and its dependence on temperature in five widely used olive cultivars. In a first experiment, cultivar differences in Rp at 25 °C were evaluated from flow-pressure measurements in excised roots and subsequent analysis of root traits. In a second experiment, similar determinations were performed continually over a 5-h period in which temperature was gradually increased from 12 to 32 °C, enabling the assessment of Rp response to changing temperature. Despite some variability, our results did not show statistical differences in Rp among cultivars in the first experiment. In the second, cultivar differences in Rp were not significant at 12 °C, but they became so as temperature increased. Furthermore, the changes in Rp between 12 and 32 °C were higher than those expected by the temperature-driven decrease in water viscosity, with the degree of that change differing among cultivars. Also, Rp at 25 °C reached momentarily in the second experiment was consistently higher than in the first at that same, but fixed, temperature. Overall, our results suggest that there is limited variability in Rp among the studied cultivars when plants have been exposed to a given temperature for sufficient time. Temperature-induced variation in Rp might thus be partly explained by changes in membrane permeability that occur slowly, which explains why our values at 25 °C differed between experiments. The observed cultivar differences in Rp with warming also indicate faster acclimation of Rp to temperature changes in some cultivars than others.
Collapse
Affiliation(s)
- Á López-Bernal
- Departamento de Agronomía, Universidad de Córdoba, Campus de Rabanales, Edificio C4, 14071 Córdoba, Spain
| | - O García-Tejera
- Efficient Use of Water Program, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Parc de Gardeny, Edifici Fruitcentre, 25003 Lleida, Spain
| | - L Testi
- Instituto de Agricultura Sostenible (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Av. Menéndez Pidal s/n, 14080 Córdoba, Spain
| | - F J Villalobos
- Departamento de Agronomía, Universidad de Córdoba, Campus de Rabanales, Edificio C4, 14071 Córdoba, Spain
- Instituto de Agricultura Sostenible (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Av. Menéndez Pidal s/n, 14080 Córdoba, Spain
| |
Collapse
|
7
|
Ding Y, Schiestl-Aalto P, Helmisaari HS, Makita N, Ryhti K, Kulmala L. Temperature and moisture dependence of daily growth of Scots pine (Pinus sylvestris L.) roots in Southern Finland. TREE PHYSIOLOGY 2020; 40:272-283. [PMID: 31860713 PMCID: PMC7048678 DOI: 10.1093/treephys/tpz131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/12/2019] [Accepted: 11/28/2019] [Indexed: 05/08/2023]
Abstract
Scots pine (Pinus sylvestris L.) is one of the most important conifers in Northern Europe. In boreal forests, over one-third of net primary production is allocated to roots. Pioneer roots expand the horizontal and vertical root systems and transport nutrients and water from belowground to aboveground. Fibrous roots, often colonized by mycorrhiza, emerge from the pioneer roots and absorb water and nutrients from the soil. In this study, we installed three flatbed scanners to detect the daily growth of both pioneer and fibrous roots of Scots pine during the growing season of 2018, a year with an unexpected summer drought in Southern Finland. The growth rate of both types of roots had a positive relationship with temperature. However, the relations between root elongation rate and soil moisture differed significantly between scanners and between root types indicating spatial heterogeneity in soil moisture. The pioneer roots were more tolerant to severe environmental conditions than the fibrous roots. The pioneer roots initiated elongation earlier and ceased it later than the fibrous roots. Elongation ended when the temperature dropped below the threshold temperature of 4 °C for pioneer roots and 6 °C for fibrous roots. During the summer drought, the fibrous roots halted root surface area growth at the beginning of the drought, but there was no drought effect on the pioneer roots over the same period. To compare the timing of root production and the aboveground organs' production, we used the CASSIA model, which estimates the aboveground tree carbon dynamics. In this study, root growth started and ceased later than growth of aboveground organs. Pioneer roots accounted for 87% of total root productivity. We suggest that future carbon allocation models should separate the roots by root types (pioneer and fibrous), as their growth patterns are different and they have different reactions to changes in the soil environment.
Collapse
Affiliation(s)
- Yiyang Ding
- Department of Forest Sciences, University of Helsinki, PO Box 27, FI-00014 Helsinki, Finland
| | - Pauliina Schiestl-Aalto
- Department of Forest Sciences, University of Helsinki, PO Box 27, FI-00014 Helsinki, Finland
- Institute for Atmospheric Sciences and Earth System Research (INAR)/Forest sciences, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Skogens ekologi och skötsel, 90183 Umeå, Sweden
| | - Heljä-Sisko Helmisaari
- Department of Forest Sciences, University of Helsinki, PO Box 27, FI-00014 Helsinki, Finland
| | - Naoki Makita
- Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto-city, Nagano, Japan
| | - Kira Ryhti
- Department of Forest Sciences, University of Helsinki, PO Box 27, FI-00014 Helsinki, Finland
- Institute for Atmospheric Sciences and Earth System Research (INAR)/Forest sciences, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland
| | - Liisa Kulmala
- Department of Forest Sciences, University of Helsinki, PO Box 27, FI-00014 Helsinki, Finland
- Institute for Atmospheric Sciences and Earth System Research (INAR)/Forest sciences, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland
- Finnish Meteorological Institute, PO Box 503, FI-00101 Helsinki, Finland
| |
Collapse
|
8
|
Rosenfeld CE, Chaney RL, Martínez CE. Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:279-287. [PMID: 29121576 DOI: 10.1016/j.scitotenv.2017.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts.
Collapse
Affiliation(s)
- Carla E Rosenfeld
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Rufus L Chaney
- Adaptive Cropping Systems Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, United States
| | - Carmen E Martínez
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, United States
| |
Collapse
|
9
|
Liu B, He J, Zeng F, Lei J, Arndt SK. Life span and structure of ephemeral root modules of different functional groups from a desert system. THE NEW PHYTOLOGIST 2016; 211:103-12. [PMID: 26856386 DOI: 10.1111/nph.13880] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/23/2015] [Indexed: 05/24/2023]
Abstract
The terminal branch orders of plant root systems have been proposed as short-lived 'ephemeral' modules specialized for resource absorption. The occurrence of ephemeral root modules has so far only been reported for a temperate tree species and it is unclear if the concept also applies to other woody (shrub, tree) and herb species. Fine roots of 12 perennial dicotyledonous herb, shrub and tree species were monitored for two growing seasons using a branch-order classification, sequential sampling and rhizotrons in the Taklamakan desert. Two root modules existed in all three plant functional groups. Among the first five branch orders, the first two (perennial herbs, shrubs) or three (trees) root orders were ephemeral and had a primary anatomical structure, high nitrogen (N) concentrations, high respiration rates and very short life spans of 1-4 months, whereas the last two branch orders in all functional groups were perennial, with thicker diameters, no or collapsed cortex, distinct secondary growth, low N concentrations, low respiration rates, but much longer life spans. Ephemeral, short-lived root modules and long-lived, persistent root modules seem to be a general feature across many plant functional groups and could represent a basic root system design.
Collapse
Affiliation(s)
- Bo Liu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Junxia He
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Fanjiang Zeng
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi, 830011, China
| | - Jiaqiang Lei
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, University of Melbourne, 500 Yarra Boulevard, 3121, Richmond, Vic, Australia
| |
Collapse
|
10
|
Bagniewska-Zadworna A, Arasimowicz-Jelonek M, Smoliński DJ, Stelmasik A. New insights into pioneer root xylem development: evidence obtained from Populus trichocarpa plants grown under field conditions. ANNALS OF BOTANY 2014; 113:1235-47. [PMID: 24812251 PMCID: PMC4030819 DOI: 10.1093/aob/mcu063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 03/06/2014] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS Effective programmed xylogenesis is critical to the structural framework of the plant root system and its central role in the acquisition and long-distance transport of water and nutrients. The process of xylem differentiation in pioneer roots under field conditions is poorly understood. In this study it is hypothesized that xylogenesis, an example of developmental programmed cell death (PCD), in the roots of woody plants demonstrates a clearly defined sequence of events resulting in cell death. A comprehensive analysis was therefore undertaken to identify the stages of xylogenesis in pioneer roots from procambial cells to fully functional vessels with lignified cell walls and secondary cell wall thickenings. METHODS Xylem differentiation was monitored in the pioneer roots of Populus trichocarpa at the cytological level using rhizotrons under field conditions. Detection and localization of the signalling molecule nitric oxide (NO) and hydrogen peroxide (H2O2) was undertaken and a detailed examination of nuclear changes during xylogenesis was conducted. In addition, analyses of the expression of genes involved in secondary cell wall synthesis were performed in situ. KEY RESULTS The primary event in initially differentiating tracheary elements (TEs) was a burst of NO in thin-walled cells, followed by H2O2 synthesis and the appearance of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling)-positive nuclei. The first changes in nuclear structure were observed in the early stages of xylogenesis of pioneer roots, prior to lignification; however, the nucleus was detectable under transmission electron microscopy in differentiating cells until the stage at which vacuole integrity was maintained, indicating that their degradation was slow and prolonged. The subsequent sequence of events involved secondary cell wall formation and autophagy. Potential gene markers from the cinnamyl alcohol dehydrogenase (CAD) gene family that were related to secondary wall synthesis were associated with primary xylogenesis, showing clear expression in cells that undergo differentiation into TEs and in the thin-walled cells adjacent to the xylem pole. CONCLUSIONS The early events of TE formation during pioneer root development are described, together with the timing of xylogenesis from signalling via NO, through secondary cell wall synthesis and autophagy events that are initiated long before lignification. This is the first work describing experiments conducted in planta on roots under field conditions demonstrating that the process of xylogenesis in vivo might be gradual and complex.
Collapse
Affiliation(s)
| | - Magdalena Arasimowicz-Jelonek
- Department of Plant Ecophysiology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Dariusz J Smoliński
- Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland
| | | |
Collapse
|